function truthCheck(collection, pre) {
    // 每个都是真的吗？
    return collection.every(item => item[pre]);
}

truthCheck(
    [
        { user: "Tinky-Winky", sex: "male" },
        { user: "Dipsy", sex: "male" },
        { user: "Laa-Laa", sex: "female" },
        { user: "Po", sex: "female" }
    ],
    "sex"
);
